Control head for oil and gas wells



Dec. 15, 1931..

w. B, wiGLE GONTRDL HEAD FOB. OIL AND GAS WELLS Filed'Jan. 11, 1930y LEN@ Patented Dec. 1.5., 1.931

PATENT OFFICE B. WIG-LE, F COMPTON, CALIFORNIA CONTROL HEAD FOR OIL LAND GAS Application lcd January 11, 1930. Serial No. 420,121.

This invention relates generally to oil well equipment, more specifically to casing control heads, and is an improvement over my co-pending application filed December 24,

1928, bearing Serial No. 328,154.

The main object of this invention is to provide a casing control head vfor oil wells constructed in sucha manner that space between two strings of casing may be packed ofi in the control head on the first string without any fittings projecting above the last or upper coupling on the second string while drilling a hole Jfor the next string of casing or tubing. y

Another object of this invention is to provide a casing head for oil wells constructed in such a manner that the oil string or tubing may be packed off at any required point and held against downward vmovement by 2o slips placed in the control head.

A further object of this invention is to provide a casing head for oil wells in which a fluid tight seal -may be made between two strings of casing in a control head while drilling vfor the next string of casing without any danger of the packing being dislodged or blown out of the control headvdue to gas pressure developed in the casing below the packing.

A still further object of this invention is to provide a casing head construction in which two strings of casing may be packed off and the hole for the next string drilled Without Jche necessity of applying a control head for said next string of casing until it has been landed.

Other objects and advantages will be apparent from the 'following descriptiomrcference being had to the accompanying drawings, in which:

Fig. 1 is avertical section taken through a plurality of well casings and tubing showing the improved casing control headv in connection therewith;

Fig. 2 is a horizontal section taken on lino 2 2 of Fig. 1;

Fig. 3 is a vertical section similar to Fig. 1 showing a modified form in which casing slips are employed to support the casing dur ing cementing operation.

Referring more specifically to the drawings, particularly to Fig.'1, 10 designates the first string of casing or water string which has been landed and cemented in the usual manner in a .well hole. The control head generally designated at 12 consists of a member 14 secured to the upper end of the casing by screw threaded connections 15 and is provided with outlets 16 from which extend the usual vent pipes 17 controlled by valves not shown. The member 14 is provided with a seat 20 adapted `to receive a bushing 22 upon which is mounted a packing ring 24 formed of resilient material, and a metallic ring 28.

The above packing rings and bushing'are formed in segments (see Fig. 2) in order that they may be placed in the member 14 around the second string of casing or tubing 28, the bushing and packing rings being placed in the control head when the tubing is in a position to be landed in an oil Zone, or cemented in as the case may be.

When the tubing serves as an oil string its uppermost coupling 30 engages the upper metallic ring 26, the weight ofthe tubing compressing the resilient packing ring 24. If it is necessary to cement the tubing 28 the coupling 3() is lowered to a point below the control head, the tubing is' then stretched sufficiently after the cement has set to bring the couplingy to a posit-ion so that its bottom face will rest on the packing when releasedfthe section of tubing extending above the coupling 30 is then removed.

After thel tubing 28 has been landed as above described, a collar 32v is applied to thev member 14 by a screw threaded connection 34 and serves to holdthe packing rings in place 9 in the member 14 against upward displacement due to any excessive gas pressure developed between the casing l0 and tubing 28, the collar having a shoulder 35 engaging the upper ring 26.

Should it be desired to bring the well in after the second string 28 has been landed, a Christmas tree77 coupling (not shown) may be secured to the upper end of the collar 32 which is internally threaded as indicated at 36 to receive such fitting or a second control head member designated at 38 if the second string 28 is cemented in above the oil sands.

During drilling of the hole for the last string 40 the second control head need not be connected, as the first and second are then packed off, it being particularly noted that the upper end of the coupling 30 projects above the upper end of the collar 32, thereby protecting it against damage particularly to the internal threads therein by the tools employed while drilling the hole for the third or last string 40.

After the hole for the last string has been completed a pair of packing rings 42 formed of resilient material are placed in the bore 44 formed in the collar 32, the packing ring encircling the lower end of the coupling 30 and resting on the upper ring 26. The second control head member 38 is then screwed into the fitting, the action of which compresses the packing rings 42 and forms a Huid tight joint by engagement between the upper face 45 of the coupling 30 and a shoulder '46 formed on the interior of the member 44.'

A split bushing 48 is placed in the upper end of the control head member 38 upon which is mounted a split packing ring 45 formed of resilient material engaged by a split metallioring 46 which in turn is engaged by the upper coupling 47 of the string 40, it being understood that the above packing need not be positioned in the member 44 until the last string is ready to be landed.

The length of the tubing projecting above the coupling is removed and the third control head 50 is secured to the member 44 by screw threaded joint 51 also compressing packing rings 52 placed in the bore 53 formed therein and resting on the upper ring 46, the second control head is provided with the usual flow or outlet pipes 54.

The upper control head 50 is provided with threaded openings 56 from which extend the flow pipes 57, and is also provided with male and female threads 58 and 60 respectively to which the usual Christmas tree (not shown) may be connected.

Under certain conditions it is necessary to land and cement a string of casing or tubing ata point between the couplings. This is accomplished by the construction shown in Fig. 3, andconsists of a control head member 62 screw threadedly connected to the iirst string of casing 63, and is provided with outlet pipes 64 extending from threaded openings entering a bore 65 terminating in a tapered bore 66 adapted to receive a plurality of slips 67.

After the second string of casing 68 has been lowered to the required depth in the well hole for cementing it in, the slips 67 are placed in the bore 66 at which time their teeth engage the wall of the second string and thereby prevent downward movement of it.

The length of tubing projecting above the control head is then cut off a short distance above the slips and a coupling 70 secured thereto preferably by welding, the underside of which engages a split ring 71 adapted to expand a resilient packing ring 72 resting on the upper face of the slips, it being understood that the casing is stretched prior to placing the packing and rings on the slips, the packing being expanded on release of the casing, it being also understood that the slips do not immediately engage or grab the casing when released, thereby permitting expansion of the packing ring.

Upward displacement of the packing rings due to gas pressure developed between the strings of casing is prevented by a fitting 74 having a shoulder 75 engaging the ring 71 and connected to they member 62 -by screw threads 76.

The third or last string of tubing 78 eX- tends through a control head generally designated at 80 which consists of a member 81 adapted to expand rubber packing rings 82 positioned in the fitting 74. Slips 84 are mounted in the tapered bore 85 of the member 81 and serve to hold the tubing 78 against downward movement until it may becemented in and packed oi.

I claim:

1. A casing head for wells comprising a body member adapted to be connected to a string of well casing landed in a well, said member having a seat formed in its upper end, a metal bushing in said seat, a resilient packing ring mounted on said bushing, a tubing string having a coupling, a metal ring disposed on said packing ring for engaging said coupling and receiving the weight of said tubing string, a collar having a shoulder formed thereon engaging the metal ring and connected to said body member for compressing the resilient packing ring to form a Huid tight seal between said casing and said tubing string when landed Vin the well, and a second body member screw threaded into said collar to form a fluid tight joint between said coupling on the tubing string and said collar.

2. A casing head for oil wells comprising a body member adapted to be connected to a string of well casing, said member having an internal seat formed in its upper end, a split metal bushing in said seat, a resilient packing ring mounted upon said bushing, a tubing string, a coupling secured to said tubing, a

metal ring disposed on said packing ri adapted to be engaged by the shoulder of sai coupling when sai tubing string is landed in the well, the weight of the tubing string compressingrsaid packing ring to form a seal between the casmg and tubing strings, and a collar threadedly connected' to said control head :lorl applying additional pressure to said resilient packing ring, a second body member screw threaded into said collar, a plurality ci resilient packing rings in said collar rest- .ing o said metal ring therein, said second body member compessing the resilient packingrrings in said collar and at the same time forming a fluid tight seal between the coupling on the tubing strin and said collar.

In testimony whereof aix my si 'ature.

. WILSON vB. WI LJE.v 

